Process of preparing beta sulpho phthalic acid



Patented Jan. 28, 1930 J J V UNITE!) STATES PATENT OFFICE HAIFS' MILDNER, OF LEVERKUSEN, GERMANY, ASSIGNOR TO GENERAL ANILHIE WORKS, INC., 01 NEW YORK, N. Y., A CORPORATION OF DELA'W lBE 5 rnpcnss or'rRnr-Anme BETA SULPHO rn'rnALIc Acrn No Drawing. -Appl ication filed September 4, 1928, Serial No.

The present invention relates to B-sulphostrength in the presence of a small amountof phthahc acid and to a process of preparing 1n same.

furic acid in the presence of a small amount of a compound of the group comprising mercury and salts and oxides thereof, ,B-sulphophthalic acid is obtainable in arconvenient manner. Advantageously the reaction may be performed with a fuming sulfuric acid of about -25% S0 content and at a temperature of about 110150 C. When working according to these conditions the sulphonated l phthalic acid of the probable formula:

, coon no.8 coon or the corresponding anhydride is obtainable in a nearly quantitative yield.

The following example-illustrates my invention without limitingit thereto, the parts being by weight:

Q '25 l art-0f phtllalic a y is heated to about 130 C. with 5 parts of 20% fuming sulfuric acid with the addition of 0,2 t parts of mercuric sulfate for about 6-10 hours. After that time the mixture'is cooled,

: poured into water and the fl-sulphophthalic acid is isolated'by salting out. It forms in form of its alkali metal salts a nearly colorless powder easily soluble in water, nearly m insoluble in the usual organic solvents. In the above example-the mercuric sulfate may be replaced by metallic mercury on another suitable salt or oxide of mercury.

1. Process of producing B-sulpho-phthalic 308,952, and in Germany June 14, 1927.

ercuric sulfate.

In testimony whereof I have hereunto set I have found that when reacting upon [my hand. 1

. HANS MILDNER. [1,. s.]

5 phthalic acid anhydride, with fuming sul- 

